This paper describes a system that allows users who obtain a “wearable ID key” to personalize dynamically ubiquitous computers by simply touching them. We call the concept of providing personalized service by touch “Active Personalization”. For active personalization, users only have to wear a digital key and do not have to carry around other computers. When users touch ubiquitous computers with their wearable key, the keyholes of the ubiquitous computers recognize their IDs and can personalize the computers. We developed a new network technology between keys and keyholes that enables digital information to be carried through a person's body based on a near-field technology we call TouchNet.